The present invention relates to an electrode tensile test method and apparatus for testing the tensile strength between a substrate and an electrode by using a probe, a substrate/probe support device for an electrode tensile test, and an electrode-probe bonding device for an electrode tensile test.
Packaging high integration density is recently demanded to reduce the cost of electronic devices in computers, automobiles, home electric appliances, and the like and to downsize them into small, low-profile devices. Among several high-density packaging methods that are currently available, a packaging method using a bump electrode (e.g., BGA, CSP, flip chip, TAB, or the like) attracts attention because it requires a smaller bonding area than other packaging methods while providing a high bonding strength.
The reliability of the packaging method of this type include the tensile strength between a bump electrode and a substrate land. In order to examine this tensile strength, a bump electrode tensile test is generally used.
As an electrode tensile test method of this type, for example, the method disclosed in Japanese Patent Laid-Open No. 8-111417 is known. According to this method, a probe is directly heated by using a heater. A bump electrode is fused with the heat of the probe and is bonded with the probe. Then, the probe is pulled to test the bonding strength between the bump electrode and the substrate.
An actual packaging process, however, does not heat only a member to be connected to the bump electrode. When the above prior art is used, the substrate and the electrode as the members to be tested undergo a temperature condition different from that in the actual packaging process, and the resultant tensile strength is sometimes different from that of an actual product.
In the method disclosed in Japanese Patent Laid-Open No. 8-111417 described above, each time one bump is to be measured, a procedure including heating, fusion, cooling, and measurement must be performed. Hence, measurement takes time.
The present invention has been made in order to solve the problems of the prior art, and has as its object to provide an electrode tensile test method and apparatus which can provide test results of an electrode tensile strength closer to that obtained in a packaging process, a substrate/probe support device for an electrode tensile test, and an electrode-probe bonding device for an electrode tensile test.
It is another object of the present invention to provide an electrode tensile test method and apparatus, which can run an electrode tensile test efficiently, a substrate/probe support device for an electrode tensile test, and an electrode-probe bonding device for an electrode tensile test.
According to the present invention, the foregoing object is attained by providing an electrode tensile test method of fixing a probe and an electrode on a substrate to each other, and pulling the probe, thereby testing the tensile strength of the electrode with respect to the substrate, comprising: an electrode fusing step of fusing the electrode; an inserting step of inserting the probe into the electrode fused by the electrode fusing step: a cooling step of cooling the electrode, into which the probe has been inserted by the inserting step, together with the probe; and a measuring step of pulling the probe, fixed to the electrode through the cooling step, from the substrate, and measuring the tensile strength between the electrode and the substrate.
In a preferred embodiment, the inserting step is the step of inserting the probe into the fused electrode using the weight of the probe itself.
According to the present invention, the foregoing object is attained by providing an electrode tensile test method of fixing a probe and an electrode on a substrate to each other, and pulling the probe, thereby testing the tensile strength of the electrode with respect to the substrate, comprising: an inserting step of inserting the probe into the electrode; an electrode fusing step of directly applying heat to the electrode into which the probe has been inserted, thereby fusing the electrode; a cooling step of cooling the electrode, fused by the electrode fusing step, together with the probe; and a measuring step of pulling the probe, fixed to the electrode through the cooling step, from the substrate, and measuring the tensile force between the electrode and the substrate.
In a preferred embodiment, the electrode fusing step is the step of increasing an ambient temperature of a space including the probe and the electrode.
In a preferred embodiment, the electrode fusing step comprises heating the substrate and the probe in a reflow furnace.
In a preferred embodiment, the electrode fusing step is the step of placing the substrate and the probe in a chamber, and blowing heated air into the chamber, thereby heating the interior of the chamber.
In a preferred embodiment, the electrode fusing step comprises blowing at least nitrogen into the chamber.
In a preferred embodiment, the electrode fusing step comprises the step of applying heat to the electrode through the substrate.
In a preferred embodiment, the inserting step is the step of arranging the substrate above the probe and inserting the probe facing up into the electrode facing down.
In a preferred embodiment, the inserting step comprises the positioning step of defining a position of the substrate with respect to the probe.
In a preferred embodiment, in each of the electrode fusing step, the inserting step, and the cooling step, a plurality of electrodes on one substrate and a plurality of probes corresponding thereto are processed simultaneously.
Further, according to the present invention, the foregoing object is also attained by providing an electrode tensile test apparatus for fixing a probe to an electrode and pulling the probe, thereby testing the tensile strength of the electrode with respect to a substrate, comprising: electrode fusing means for directly applying heat to the electrode, thereby fusing the electrode; and measuring means for pulling the probe which is inserted in the electrode fused by the heating means and is cooled so as to be fixed to the electrode, from the substrate, and measuring a tensile force between the electrode and the substrate.
In a preferred embodiment, the electrode fusing means is heating means for increasing the ambient temperature of space including the probe and the electrode.
In a preferred embodiment, the heating means is a reflow furnace.
In a preferred embodiment, the heating means comprises: a chamber in which the substrate and the probe are placed; and means for blowing heated air into the chamber, thereby heating the interior of the chamber.
In a preferred embodiment, the heating means has means for blowing at least nitrogen into the chamber.
In a preferred embodiment, the electrode fusing means comprises substrate heating means for heating the substrate in order to transmit heat to the electrode through the substrate.
In a preferred embodiment, the apparatus further having: substrate support means for supporting the substrate; and probe guiding means for guiding the probe to the electrode.
In a preferred embodiment, the probe guiding means guides a plurality of probes to a plurality of electrodes simultaneously.
In a preferred embodiment, the substrate support means supports the substrate to face down; and the probe guiding means supports the probe to face up; wherein the substrate support means and the probe guiding means being arranged such that the substrate is located above the probe.
In a preferred embodiment, the substrate support means has positioning means for defining the distance between the distal end of the probe and the substrate.
In a preferred embodiment, the probe has a rod-like portion, and a distal end portion to be fixed to the electrode, the probe guiding means is a plate-like member having a probe inserting hole with a larger diameter than that of the rod-like portion, the substrate support means has a support for supporting the plate-like member to be substantially parallel to the substrate, and the support serves to support the plate-like member such that, when the probe is inserted in the hole in the plate-like member and the distal end portion thereof abuts against the electrode on the substrate supported by the substrate support means, at least part of the rod-like portion of the probe projects to that side of the plate-like portion which opposes the substrate.
Further, according to the present invention, the foregoing object is also attained by providing an electrode tensile test apparatus for fixing a probe to an electrode and pulling the probe, thereby testing the tensile strength of the electrode with respect to a substrate, comprising heating means having a heater and capable of soldering an electronic component; and measuring means for pulling a plurality of probes, which are inserted in a plurality of electrodes fused by the heating means and cooled so as to be fixed to the electrodes, and measuring a tensile force between the electrode and the substrate.
Further, according to the present invention, the foregoing object is also attained by providing a substrate/probe support device for an electrode tensile test for fixing a probe and an electrode on a substrate to each other by using heating means which increases an ambient temperature, and pulling the probe, thereby testing the tensile strength of the electrode with respect to the substrate, comprising substrate support means for supporting the substrate, and probe guiding means for guiding the probe to the electrode on the substrate supported by the substrate support means.
In a preferred embodiment, the probe guide means has a plate-like member having a probe inserting hole, the substrate support means has a support for supporting the plate-like member to be substantially parallel to the substrate, and the support serves to support the plate-like member such that, when the probe is inserted in the hole in the plate-like member and the distal end portion thereof abuts against the electrode on the substrate supported by the substrate support means, at least part of the rod-like portion of the probe projects to that side of the plate-like portion which opposes the substrate.
Further, according to the present invention, the foregoing object is also attained by providing an electrode-probe bonding device for an electrode tensile test, comprising heating means having a heater and capable of soldering an electronic component, substrate support means for supporting the substrate, and probe guiding means for guiding the probe to the electrode on the substrate supported by the substrate support means.
In a preferred embodiment, the guiding means guides a plurality of probes to a plurality of electrodes on the substrate.
In a preferred embodiment, the heating means comprises a chamber in which the substrate and the probe are placed, and means for blowing heated air into the chamber, thereby heating an interior of the chamber.
In a preferred embodiment, the heating means further comprises means for blowing at least nitrogen into the chamber.
In a preferred embodiment, the heating means comprises substrate heating means for heating the substrate in order to transmit heat to the electrode through the substrate.
In a preferred embodiment, the substrate support means supports the substrate to face down, the probe guiding means supports the probe to face up, and the substrate support means and the probe guiding means are arranged such that the substrate is located above the probe.
In a preferred embodiment, the substrate support means has positioning means for defining the distance between a distal end of the probe and the substrate.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.